SEATTLE -- James Paxton said he felt great on Wednesday after throwing three innings in his second rehab start for Triple-A Tacoma on Tuesday night, which is no small step for the rookie left-hander.

The first time Paxton went through the rehab process this year following a strained lat muscle, he had to be shut down after experiencing further pain in his shoulder the day after his first rehab start. But he's now two outings into his latest return, and no red flags have been raised.

Paxton said he expects to make his next rehab start Sunday in Tacoma in a 1:35 p.m. PT game against Sacramento, then will see what happens.

"It's a big deal to be able to come back the next day and play catch and have no pain," Paxton said Wednesday after rejoining the Mariners at Safeco Field. "It's a good feeling."

Paxton had a rough first inning Tuesday against Las Vegas and wound up allowing three runs (two earned) on three hits with a walk and four strikeouts in his three frames. But the 6-foot-5 southpaw finished strong, retiring eight of the last nine batters faced, and said things are heading in the right direction.

"The last two innings were really good," he said. "That felt closer to normal for me. The first inning I was aiming the ball a little and it just felt like I was pushing the ball in there a little bit. But then I just tried to forget about location a little bit and just go after guys like I do when I'm feeling good, and it worked out a lot better for me, as the results showed. I definitely made progress in that start and I feel like next time out, I'll keep on making progress."

Manager Lloyd McClendon says Paxton will need at least one more rehab start, but is happy to see positive steps from a pitcher who has gone 5-0 with a 1.75 ERA in six Major League starts.

"I was very pleased," McClendon said. "He got it up to 70 pitches -- 60 in the game and 10 in the bullpen. And he felt good, so that was big."